Treatment of NZB/NZW mice with Ribavirin, a broad spectrum antiviral drug, has been very effective. Renal deposits of immune complexes can be prevented. Such treatment is potentially applicable to humans with SLE. Male sex hormones, testosterone and 5 alpha-dihydrotestosterone (but not Danazol) prolonged life in female NZB/NZW mice. Such treatment was effective even when started after clinical illness and did not require castration for its full effect. However, NZB mice are much less sensitive to androgen administration. A diet enriched in a polyunsaturated fatty acid markedly retards the development of autoimmunity in (NZB x NZW) F1 females. Thymectomy markedly retards autoimmunity in MRL/1pr/1pr mice.